1. Field of the Invention
The invention relates to a technique of performing surface treatment such as plating on a thin plate.
2. Description of the Related Art
When surface treatment such as plating is performed on a substrate and the like, it has been common to use a method of immersing the substrate in a plating bath that is filled with a plating solution. This method requires a lifting mechanism to lift and lower the substrate, which leads to a problem of complication and enlargement of a device. In addition, the plating bath has to be filled with the plating solution, which leads to a problem of requiring a large quantity of the plating solution. These problems are not only inherent in plating but are common to the surface treatment as a whole. Note that the surface treatment includes treatment of a surface of a target such as electroless plating, electroplating, displacement plating, displacement reduction plating, zincate treatment, pretreatment, post treatment, desmear, catalyst-imparting, activator, accelerator, etching, and various types of cleaning.
In order to solve such problems, the inventors have invented a device that releases a treatment solution to the substrate whose upper portion is held, collects the treatment solution dropped from the substrate, and releases the treatment solution again (JP-A-2014-88600, JP-A-2014-43613).
FIG. 22 shows a surface treatment device disclosed in JP-A-2014-88600. An upper portion of a substrate 2 is held by a hanger 6 as a holding member. A mobile body 14 that holds the hanger 6 is held by a roller 16, and moves in a perpendicular direction to the sheet. The substrate 2 is introduced into a body 4. In the body 4, a treatment solution releasing section 8 that has a treatment solution jet port 10 is provided on each side of the substrate 2.
The treatment solution is jetted to the substrate 2 from the treatment solution jet port 10, and the treatment solution that has reached the substrate 2 flows down on a surface of the substrate 2. In this way, the surface of the substrate 2 is treated by the treatment solution.
The treatment solution that has run down is collected in a lower portion of the body 4 and is released again from the treatment solution releasing section 8 by a pump 12.
In this way, a reduction in use of the treatment solution is realized without enlarging and complicating the device.
In the above related art, the released treatment solution is applied to the substrate 2 and flows down. Thus, such a problem is raised that a portion of the substrate 2 above a position applied with the treatment solution cannot be subjected to the surface treatment and becomes useless.
Furthermore, it is difficult to keep a force of releasing the treatment solution to be constant, which leads to such a problem that the position of the substrate 2 applied with the treatment solution varies and thus the position in the upper portion of the substrate that is subjected to the surface treatment also varies.
The invention solves the above problems and therefore has a purpose of providing a device capable of thoroughly performing surface treatment to an upper portion of a substrate.